Apparatus for making capillary tubes



K. L. TATE APPARATUS FOR MAKING CAPILLARY TUBES March 1l., 1930.

Filed March 19, 1929 lNVENTOR 1 www 1^ 926/ ATTORNEY Patented Mar. 11,' 1930 UNITED STATES PATENT OFFICE KENNETH L. TATE, OF ROCHESTER, NEVI YORK, ASSIGNOR TO TAYLOR INSTRUMENT COMPANIES, F ROCHESTER, NEW YORK, A CORPORATION 0F NEW YORK APPARATUS FOR MAKING- CAPILLARY TUBES Application led March 19, 1929. Serial No. 348,344.

This invention relates to apparatus for making capillary tubes such as are used in connection with mechanical distance thermometers.

In the patent to Hodgkinson No. 1,063,349 is described a capillary containing a wire for reducing the capillary bore volume. In the application of D. D. Rosenburgh, Ser. No. 142,632, filed on Oct. 19, 1926, is described a capillary wherein the surface of the capillary bore is substantially smooth and uniform and the clearance between the wire and the bore is reduced to a small fraction of the clearance involved in the Hodgkinson patent.

It is the object of the present invention to provide apparatus for forcing a wire into a capillary whose bore is smo-oth and uniform but of a diameter not more than about .0015 greater than the diameter of the wire.

For a full understanding of the invention, reference is made to the accompanying drawings, wherein Fig. 1 is a more or less diagrammatic elevational view of apparatus embodying the invention;

Fig. 2 is a sectional view taken on line 2 2, Fig. 1;

Fig. 3 is a section, on an enlarged scale of part of the mechanism shown in Fig. 1 and Fig. 4 is a section taken on line 4 4, Fig. 3.

Having reference to Fig. 1, 1 is a reel containing the wire 2 to be forced into the capillary 3. The latter is supported on a bench 4 in bearings adapted to hold it in a substantially straight line for rotation. In the particular arrangement disclosed, the bench, which may have any desired length, carries a plurality of brackets 5 spaced about 2-3 ft. apart, each bracket having a V-shaped configuration defining at the apex of the V a notch 5a rounded at the bottom to support the capillary 3. Adjacent the brackets are arcuate arms 6 supported upon a rod 7 which extends substantiallythe whole length of the bench 4 and is mounted in bearings 8 and 9 for rotation by a handle 10. The arms may be swung to one side, as shown in dotted line in Fig. 2, so that the capillary may be en"'- tered in the notches 5a and then the arms are 0 swung back over and across the brackets to form looking bars preventing the capillary from moving upwardly. The brackets, being in alignment with each other, hold the capillary in a straight line.

To reduce friction, the arms 6 carry pieces of leather 6a or the like, projecting slightly below the lower edge of the arms to bear upon the capillaries.

Mechanism is provided for feeding the wire 2 from the reel 1 into the capillary 3 and for rotating the latter at the same time.

The end of the capillary 3 into which the Y wire is to be fed, is supported in a bearing 11 having a flaring mouth 11a to facilitate the entering of the capillary. The inner end of the mouth 11a receives the capillary with just sufficient clearance to avoid undue friction during rotation of the capillary 3.

The bearing 11 has an extension 12 in axial alignment with the mouth 11, said extension having an axial bore 13 concentric with and leading into the mouth 11a. This arrangement makes it possible that the wire 2 may be passed into the capillary without any intervening gap.

The wire 2 is passed through a curve-d, preferably S-shaped tube 14 between two rolls 15 which are rotated by a motor 16 and suitable transmission mechanism including a reducing unit 17 and force the wire into the capillary 3. The rolls 15 are provided with aligned grooves 18 of preferably semicircular cross-section and are forced toward each other by spring pressure. In the particular arrangement, the rolls are mounted in a frame 19 on shafts 20. The shaft of the lower roll is journaled directly in the frame 19, while the shaft of the upper roll is journaled in a yoke 21 movably mounted in guideways 21a in frame 19. The latter has a turret-like part 22 bored t0 provide a housing for a piston element 23. a spring 24 and an abutment plate 25. This plate 25 may be adjusted by means of a screw 25a or the like, to vary the pressure of the spring 24 upon the piston 23 and through it upon the upper roll 15.

For the rotation of the capillary, I have provided a chuck 26 mounted between the bearing 11 and the bench 4 and driven by a motor 2T. The chuck including the handle 28, the pulleys Q9 and the mounting 30 may be of a. usual or standard construction and does not, as such, form part of the invention.

rllbe operation is as follows:

The Wire 9. is initiallypassed by hand through the curved tube let, the grooves 18 of the rolls 15 into the bore 13 ot the extension 1:2 far enough to cause it to enter the capillary 3. Then the motor QT and the motor 1o are started in succession.

yllhe mechanism for turningthe rolls is so designed and adjusted as to normally feed the wire ata speed ot about 20 ft. per minute and the mechanism for rotating the capillary 8 is so chosen as to normally impart to the capillary a speed or about 1200 R. l). h/I.

It is understood that the si eeds referred to are by no means invariable, but merely represent what I have tound to be a very satisfactory arrangement. The ratio of rotary speed to axial speed is very high and in the particular instance referred to equals revolutions for 1 or revolutions for 1 ot axial feed. The practical significance oit this ratio is that the motion necessary to enter the Wire has been split up into tivo components, an axial component and a lateral component defining in conjunction a sinusoidal path aeeording to equation f/:a sin au The resistance opposing the entering of the -Wire is therefore materially reduced. I have found that a Wire having a diameter ot .029 may be readily forced into a capillary having a bore of .030 diameter, which would be impossible by linear movement alone.

The rolls 15 being continuously and uniformly driven, the feed is generally uniform but may, in case of emergency, adapt itself to conditions and even stop Without material damage to the ivire. The tension of spring 24 may be so adjusted as to provide the normal gripping action necessary to overcome the resistance otiered by the bore of the tube. In case an unusual resistance is encountered such as could not be immediately overcome by the drilling action of the wire, the rolls Will slip and the operator Will soon discover it.

Since the Wire is coniined in a bearing extending close to the feed point of the rolls 15 and the extension 12 is in axial alignment With the plane of Contact of the rolls, a considerable axial pressure ma;7 be exerted on the Wire Without danger of buckling even with .wires of diameters of the order of .01. In other Words, the axial thrust may be a maximum.

The curved tube 14 has the purpose to set up a large resistance against Atorsional motion of the Wire which might be induced by the rotary movement of the capillary.

The grooves 1S are preferably semi-circular to avoid as much as possible distortion of the surface of the Wire and yet obtain an effective gripping action.

llVhile I have described what I consider at present as the best and preferred embodiment of my invention, I Want to have it understood that there is considerable latitude in various directions.

I claim:

1. Apparatus for entering` a wire into a flexible tube, comprising means deiining a plurality of aligned bearings constructed and arranged to maintain the liexible tube in a substantially straight line and free to be rotated, means for rotating the tube and means for continuously feeding the Wire into the tube.

2. Apparatus for entering a Wire into a flexible tube, comprising a bearing constructed and arranged to hold one end of the tube free to undergo rotary motion about a fixed axis of rotation, a plurality of bearings in axial alignment with said bearing, constructed and arranged to permit rotation of the tube and to maintain the tube during rotation in a straight line, means for rotating the tube f and means for continuously feeding the vvire into the said end of the tube.

3. Apparatus for entering a wire into a flexible tube, comprising a plurality of axially aligned bearings having lateral openings for receiving the tube in a direction at right angle to its direction of length, means for closing said openings and for maintaining the tube in a substantially straight line, a` bearing for one end of the tube, constructed and arranged to receive the tube in axial direction and to maintain it in axial alignment with the other bearings, means tor rotating the tube and means tor continuously feeding the Wire into the tube.

Ll. Apparatus for entering a wire into a flexible tube, comprising a bearing for one end of the tube permitting rotation ot the same about a iixed axis, a support for the tube extending from the opposite end to near said bearing, for maintaining the tube in a substantially straight line, means between said bearing and said support for rotating the tube and means tor feeding the Wire into the tube at the end held in said bearing.

Apparatus tor entering a wire into a capillary tube, comprising a member having two aligned concentric bores, a larger bore tor receiving one end of the capillary tube and a smaller bore 'for conducting the Wire into the bore of the said capillary tube, said smaller bore being substantially ot the size of the bore of the capillary tube.

6. Apparatus for entering a Wire into a capillary tube, comprising a member having tivo aligned concentric bores, a larger bore tor receiving one end ot the capillary tube and a smaller bore for conducting the wire into the bore of the capillary tube, the smaller bore being substantially of the size of the bore of the capillary tube, means for feeding the wire into the said smaller bore and means for rotating the capillary tube about the axis of the larger bore.

7. Apparatus for entering a wire into a capillary tube, including a member having a bore for receiving one end of the capillary tube and holding the same for rotation about a fixed axis, the said member also having a smaller bore in axial alignment with the larger bore for conducting the wire into the bore of the capillary tube, the smaller bore having substantially the size of the bore of the capillary tube and the outer ends of the bores flaring outwardly to facilitate the entering of the capillary tube and the wire respectively.

8. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis including a bearing at one end, means intermediate the ends of the tube for rotating the same, means adjoining the said bearing for conducting the wire into the bore of the flexible tube and means immediately adj aeent the said conducting means for moving the wire in axial direction.

9. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis, means for rotating the tube, means for axially moving the wire and means between the moving means and the tube for holding the wire in axial alignment with the latter.

10. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis, means for rotating the tube, means for axially moving the wire, means between the moving means and the tube for holding the wire in axial. alignment with the latter and means in advance of the moving means acting upon the wire to oppose rotary movement thereof.

11. Apparatus ,for entering a wire into a flexible tube. comprising means for revolubly support-ing the tube about a fixed axis, means for rotating the tube, means for axially moving the wire and means connected with the wire in advance of the tube, tending to oppose rotary movement of the wire.

12. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis, means for rotating the tube, resiliently yielding means for axially moving the wire and means in advance of the moving means, tending to oppose rotary movement.

13. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis, means for rotating the tube, means for conducting the wire into the tube and resiliently yielding means in advance of the conducting means for axially moving the wire.

14. Apparatus for entering a wire into a flexible tube, comprising means for revolubly supporting the tube about a fixed axis, means for rotating the tube, means for conducting the wire into the tube, means act-ing upon the wire, tending to oppose rotary movement thereof, and resiliently yielding means for axially moving the wire into the tube.

15. The combination of a pair of rolls having aligned grooves, resilient means for pressing the rolls toward each other, a member having at one end a bore for receiving the end of a capillary tube and having in opposite direction in axial alignment with the bore an extension having a fine bore for conducting a wire into the said bore centrally thereof, and means for supporting said member to one side of the rolls in the plane of the grooves and substantially in the plane tangent to the points of contact between the rolls,

with the end of the said extenison in close proximity to the line of Contact between the rolls.

16. The combination of a pair of rolls having aligned grooves, resilient means for pressing the rolls toward each other, a member having at one end a bore for receiving the end of a capillary tube and having in opposite direct-ion in Vaxial alignment with the bore an extension having a fine bore for conducting a wire into the said bore centrally thereof, and means for supporting said member to one side of the rolls in the plane of the grooves and substantially in the plane tangent to thc line of contact between the rolls with the end of' the said extension in close proximity to the line of contact between the rolls and a curved capillary tube disposed on the other side of the rolls, having one end terminating in the plane of the grooves in close proximity to the line of contact between the rolls.

17. The combination of a pair of rolls having aligned grooves, resilient means for pressing the rolls toward each other, a member dening at one end a tubular portion for receiving the end of a capillary tube and defining at the opposite end a capillary tube having its bore in axial alignment with said tubular portion and means of supporting the said member with its axis disposed substantially in the plane of the grooves and the plane of the tangent through the point of contact between the rolls, the free end of the capillary tube portion of the said member terminating in close proximity to the line of contact between the rolls.

18. In apparatus for entering a wire into a capillary tube, the combination of means for rotating the tube about a fixed axis of rotation and means for continuously pushing the wire into the tube at a rate of approximately 1 for 60 revolutions of the tube.

19. In apparatus for entering a wire into a capillary tube, the combination of means for rotating the tube about a fixed axis of rotation, resiliently yielding means for continu- U ously pushing` the wire into the tube and means near the pushing means tending to hold the Wire against rotation.

20. In apparatus for entering a Wire into a capillary7 tube, the combination of means for rotating the tube about a fixed axis of rotation, resilient-ly yielding nieans for pushing the Wire into the tube, means between the pushing lneans and the tube for Conducting the Wire against lateral distortion and means near the pushing means tendingto hold the Wire against rotation.

In testimony whereof I aliix my signature.

KENNETH L. TATE. 

